Combination step and extension ladder



y 1959 R. c. MCKINNQIE COMBINATION STEP AND EXTENSION LADDER Filed May6, 1957 R E m NC 2 C & N A O a v. 18

United States Patent 2,887,260 COMBINATION STEP AND EXTENSION LADDERRoxton C. McKinnie, Los Angel es, C alifi 1 Application May 6, 1951,Serial No. 657,375 2 Claims. (Cl. 228-46 This invention relatesgenerally to ladders and more particularly to an improved combinationstep and extension ladder.

For general household chores, there are relatively few instances inwhich a ladder any longer than a conventional step ladder is necessary.Nevertheless, a separate longer ladder has usually been purchased forthe few instances that it may be required. More recently, combinationstep and extension ladders have been proposed in various forms to avoidthe expense of two separate ladders. Such combination step and extensionladders, however, are still more expensive than a simple step ladderalone. It would be highly desirable, accordingly, to provide a simplestep ladder which costs no more than conventional step ladders but whichmay be used in combination with an extension ladder specificallydesigned to co-operate with the step ladder to provide a relatively longladder. The design should be such that only the step ladder itself needbe puchased and should the occasion arise for the use of an extensionladder, the extension portion thereof may subsequently be bought andused in conjunction with the step ladder.

By such an arrangement of the above type, the step ladder itself need heno more expensive than a conventional step ladder inasmuch as it needinclude no compound structure for enabling it to be formed into anextension ladder, whereas the extension ladder portion itself, inasmuchas it is integrally separable from the.

step ladder, may be manufactured relatively inexpensively. Accordingly,for those instances in which an extension ladder is only occasionallyrequired, the slight added inconvenience of having to assemble the stepand extension ladder portion together would be more than overcome by theeconomies afforded and the convenience of a simple step ladder structurealone, not employing complicated folding and extension mechanismsthereon.-

With the above advantages in mind, it is a primary object of the presentinvention to provide an economical combination step and extension ladderin which the extension portion thereof may be sold individually andseparate from the step ladder portion and in which the step ladderportion itself is no more complex nor expensive to manufacture than aconventional step ladder.

More particularly, it is an object to provide a combination step andextension ladder of-the above type including novel fastening meanstherefor in which it is not possible to secure the extension ladderportion safely to the step ladder portion without first making sure thatthe step ladder portion is folded to its closed position, whereby thepossibility of the step ladder portion unfolding while the same is beingused with the extension ladder is avoided.

More general objects of the invention are to provide a combination stepand extension ladder which is extremely rugged, safe in operation,employs a minimum number of movable parts, and which may be assembled ordisassembled with great facility.

These and other objects and advantages of this invention are attainedbriefly by providing a step ladder portion in conventional form with theexception that the front legs of the step ladder extend beyond theuppermost step thereof and terminate in end surfaces inclined forwardlyand downwardly. Preferably, the step ladder also includes theconventional pail shelf which may also serve asa spreader support forthe rear legs. The pail shelf portion is disposed further forwardly thanis conventional in order that toe room will be provided for the stepsadjacent the pail shelf when the step ladder is in a folded position.

The extension ladder portion includes a pair of extension legssupporting several steps therebetween. The lower ends of these extensionlegs are spaced somewhat further apart than the upper end of the frontlegs of the step ladder such that the lower ends of the extension legsmay straddle the upper ends of the front legs of the step ladder.Suitable blocks are secured to the inside of the extension ladder legsand include inclined lower ends adapted to seat on the inclined upperends of the front legs of the extension ladder whereby the load of theextension ladder is carried by these blocks. Finally, the lower insideends of the extension legs include bracket means adapted to encompassthe upper ends of the front legs in a secure position only when the rearlegs of the step ladder portion are folded against the front legs. Thus,the bracket means serves the additional function of also preventingaccidental unfolding of the step ladder when the step and extensionladder portions are used together as an overall long ladder. The entireassembly and disassembly of the step and extension ladder is extremelysimple and may be performed by anyone without need of special tools orskill.

A better understanding of the invention will be had by referring to apreferred embodiment as illustrated in the accompanying drawings inwhich:

Figure 1 is a perspective exploded .view of the step and extensionladder of this invention; and,

Figure 2 is a view similar to Figure 1 illustrating the extension ladderportion secured to the step ladder portion when the two portions are tobe used as a single extended ladder.

Referring to Figures 1 and 2, there is shown a conventional step laddercomprising a pair of front legs 10 and 11 supporting a plurality. ofsteps 12 therebetween. Rear legs 13 and 14 are pivoted at their upperends as at 15 and 16 to the upper end portions of the front legs 10 and11. These rear legs 13 and 14 also include a conventional pail shelf 17pivotally secured between the rear legs by suitable braces 18 and 19terminating under one of the steps and secured by conventional shelflock braces such as the brace 20. The arrangement is such that the rearlegs may be spread from the lower portions of the front legs to providea stable support for the step ladder, the pail shelf 17 simultaneouslyswinging down to a horizontal position all as is well known in the art.

In accordance with one feature of the invention, the upper ends of thefront legs 10 and 11 extend beyond the top step and terminate inforwardly and downwardly inclined end surfaces 21 and 22. With thisexception, the step ladder described in Figure 1 is in all. otherrespects entirely conventional.

Also, shown in the exploded view of Figure l is an extension ladderadapted to co-operate with the step ladder, comprising a pair ofextension legs 23 and 24 supporting a plurality of steps 25therebetween. The lower end portions of the legs 23 and 24 are spacedapart a greater distance than the upper ends of the front legs 10 and 11of the step ladder such that these extension legs may straddle the stepladder legs as clearly illustrated in Figure 2. As shown, there areprovided support blocks 26 and 27 on the inside portions of theextension legs 23 and 24, each of these blocks terminating short of theends of the extension legs in ends 28 and 29, inclined to seat on theinclined surfaces 21 and 22 when the extension ladder is secured, to thestep ladder. A first pair of brackets 30 and 31 of general U- shape arealso included on the insides of the extension legs 23 and 24 to receivethe upper width of the front legs and 11. Also, included are enlargedbrackets 32 and 33 of U-shape in which the distance between the engagingU-legs is purposely made of such value as to encompass both the width ofthe front legs 10 and 11 of the step ladder plus the width of the rearlegs 13 and 14. These widths can only be accommodated by the brackets 32and 33 when the rear legs of the step ladder are folded against thefront legs thereof as illustrated clearly in Figure 2. It will beevident, therefore, that the extension ladder portion cannot be securedto the step ladder portion until the step ladder has been folded. Atthis time, the extension ladder may be inserted onto the step ladder andthe seating surfaces 28, 29 and 21, 22 properly engaged.

The operation of the combination step and extension ladder will be clearfrom the above description. When it is desired to use the step ladderonly, the rear legs 13 and 14 may be spread to the position illustratedin Figure 1, the pail shelf 17 simultaneously swinging down from itsvertical folded position shown in Figure 2 to the horizontal position,the rear ends of the braces 18 and 19 resting under the second step.

When it is desired to use the step ladder'as an extension ladder, thestep ladder is first folded to the position shown in Figure 2 and theextension ladder portion then simply positioned over the top portions ofthe legs 10 and 11 to straddle these legs. The lower ends 28 and 29 ofthe blocks 26 and 27 will then seat on the surfaces 21 and 22. It willbe noted from Figure 2 that because of the inclination of these surfacesforward anddownwardly, any tendency for the extension ladder portion toslide rearwardly as a result of a persons weight on the ladder can onlybe accommodated by the blocks, such as the block 27, sliding upwardly onthe surface 22 thereby tending to raise the extension ladder portion.Since the weight of a person on this extension ladder portion opposesthis tendency to raise, the two latter portions are effectively securelylocked together. Also, the main front legs of the step ladder carry theload rather than the rear legs. Further, the brackets 30, 31, 32 and 33are such that the bending moments established between the ladderportions are borne by the brackets rather than by the main legs.

Because of the prolonged extension of the front legs 10 and 11 on thestep ladder portion, no special rivets are required for the top step asis the case with conventional step ladders and thus there is no addedexpense in the manufacture of the step ladder over that involved inmanufacturing conventional step ladders. Finally, it will be evidentthat the extension ladder portion can only be attached when the stepladder portion is in closed position and that once the extension ladderis attached, there is no possibility of the step ladder portioninadvertently spreading to open position. As will be evident from Figure2, the pail shelf 17 is positioned sufliciently forward on the braces 18and 19 such that toe room is 4. provided whereby the combination stepand extension ladder may be effectively used as an overall regularladder of similar length.

Various modifications within the scope and spirit of the presentinvention will occur to those skilled in the art. The combination stepand extension ladder is, therefore, not to be thought of as limited tothe particular embodiment set forth for illustrative purposes.

What is claimed is:

l. A combination step and extension ladder comprising: a pair of frontlegs having a plurality of steps supported'therebetween; a pair of rearlegs pivoted. adjacent to the upper ends of said front legs,respectively, and adapted to be swung from a folded position againstsaid front legs to a spread apart position to provide a step ladder, theupper ends of said front legs extending beyond the top step of said stepladder; an extension ladder comprising a pair of extension legs spacedapart a greater distance than the upper ends of said front legs so thatsaid extension legs are adapted to straddle said front legs; a pluralityofsteps supported between said extension legs; a first pair of bracketsof general U-shape secured to opposite inside portions, respectively, ofsaid extension legs below the lowest step thereof and above the extremelower ends of said extension legs, the spacing between the U-arms ofsaid brackets being substantially equal to the width of each of saidfront legs measured from the front to the rear thereof, whereby saidbrackets receive said front legs respectively when said extension legsare positioned to straddle said front legs; and a second pair ofbrackets of general U-shape secured to opposite inside portionsrespectively of said extension legs at a given spacing below said firstpair of brackets, the spacing between the U-arms of each of said secondpair of brackets being greater than that between the U-arms of each ofsaid first pair of brackets by an amount substantially equal to thewidth of each of said rear legs measured from the front to the rearthereof so that said second pair of brackets receive both said front andrear legs only when the same are folded together, whereby said secondpair of brackets holds said step ladder in said folded position whensaid extension legs are positioned to straddle said front legs and saidgiven spacing between said pairs of brackets maintains said extensionlegs in stable alignment with said front legs.

2. The subject matter of claim 1, in which the extreme upper end of eachof said front legs terminates in a single surface inclined forwardly anddownwardly; and in which a pair of blocks are secured to the insideopposite surfaces of said extension legs between said first pair ofbrackets and the underside of the lowest step thereof, each blockterminating in a lower end surface inclined upwardly to seat on theextreme upper end of each of said front legs when said extension legsare positioned to straddle said front legs.

References Cited in the file of this patent UNITED STATES PATENTS514,223 Hammon Feb. 6, 1894 550,175 Holden Nov. 19, 1895 r 2,396,028Spayd Mar. 5, 1946 2,471,110 Jenkins May 24, 1949

